This invention relates to an apparatus and method for de-airing the heart, particularly, to a disposable apparatus for aspirating air from the left ventricle of the heart.
Cardiopulmonary bypass surgery is an extremely delicate procedure which saves the lives of many heart patients. A critical step in that procedure involves de-airing the heart after repair of the heart has been completed. If air is not evacuated from the heart, air bubbles in the blood stream could result in stroke or death. Consequently, after completing the repair of the heart and as the cardiac chambers are closed, the heart must be freed of air as much as possible before it begins to beat. Further de-airing maneuvers, however, are also necessary after cardiac action begins. The exact steps in sequences vary from surgeon to surgeon, but the principles are well known in the prior art. These are (1) the filling of the heart with fluid before closing it, to minimize air entrapment; (2) aspiration of residual air from the heart before allowing it to eject; (3) intermittent ventilation of the lungs to express air from the pulmonary veins; and (4) continuous suction on a needle vent in the ascending aorta (or a freely bleeding stab wound) as the heart commences ejecting blood to retrieve any air that may have remained in the heart or pulmonary veins.
All these known methods of de-airing the heart, however, require needle aspiration of the heart to ensure complete evacuation of air from the heart which requires that the heart be gently squeezed repeatedly to force air out of the heart through the needle. Typically, the heart is gently pulled forward and to the right without dislodging it and a needle (usually a 19 gauge injection needle is preferred) is inserted into the apex of the left ventricle. The heart is gently massaged or squeezed as the aspirating needle is reciprocated so that air collected in the left ventricle may be removed through the aspirating needle. It is difficult to determine, however, when the air has been completely evacuated from the heart. Thus, as a cautionary measure, surgeons frequently perform this manipulation many times.
A disadvantage of this known step for de-airing the heart is that it is difficult to properly position the open tip of the aspirating needle within the left ventricle so that air which collects at the top of the left ventricle is aspirated through the needle. This is particularly difficult as the left ventricle fills with blood and the tip of the aspirating needle extends below the level of blood collected in the left ventricle. As the blood level rises, the surgeon must repeatedly move the aspirating needle up and down so that the tip of the needle is above the level of the blood so that air trapped at the top of the left ventricle may be aspirated. This is a rather imprecise procedure which must be repeated many times to insure that substantially all of the air is evacuated from the heart.
Another disadvantage of this known de-airing step is that during diastole of the heart, the heart may suck air into the left ventricle through the aspirating needle. Thus, drawing more air into the heart.
The method and apparatus of the present disclosure overcomes the deficiencies of the prior art methods of de-airing the heart by providing an apparatus which eliminates the required repeated manipulation of an aspirating needle and reduces the extent and duration of manipulation of the heart.
It is therefore an object of the invention to provide an apparatus for de-airing the heart which permits a surgeon to visually determine that the heart is free of air.
It is another object of the invention to provide an apparatus for de-airing the heart by inserting a closed tip needle into the heart and permitting air to aspirate through longitudinal slots formed in the body of the needle.
It is yet another object of the invention to provide an apparatus for de-airing the heart which comprises a resilient squeezable bulb attached to an aspirating needle. The resilient bulb is provided with a valve permitting air to be expelled from the bulb thereby creating a vacuum within the resilient bulb so that air and blood may be sucked out of the heart into the bulb to make the de-airing more efficient and quicker and substantially eliminate any possibility for air being sucked into the heart.
It is another object of the invention to provide an apparatus for de-airing the heart which is sterilized, ready to use and disposable.